From the 21st of December to the 2nd of January, YouTube didn't update their anti-adblock script, but they're back to the same old shit now, with daily updates on weekdays.
Also, if you use uBO, the latest version (1.55) enables differential updates for filter lists, which will save a ton of bandwidth on the servers hosting those files. Lists now update automatically every 5 hours. That's why the "Purge caches" button has been removed. It should be noted that you can still update any individual list at any time manually, but if you do that, differential updates won't continue for that list until a full cycle has completed, which can take up to 7 days.
TL;DR - If you're using uBO 1.55, just leave it to do its thing and don't fuck around manually updating lists.